Year	Percent
1960	1.61171
1961	1.69613
1962	1.77808
1963	1.85225
1964	1.92075
1965	1.97945
1966	2.04418
1967	2.10022
1968	2.11531
1969	2.07902
1970	2.01552
1971	1.94352
1972	1.89752
1973	1.90376
1974	1.97739
1975	2.09635
1976	2.20771
1977	2.30317
1978	2.42444
1979	2.57162
1980	2.72318
1981	2.89545
1982	3.02383
1983	3.02512
1984	2.87305
1985	2.63202
1986	2.35417
1987	2.13726
1988	2.04767
1989	2.12585
1990	2.30935
1991	2.51404
1992	2.65735
1993	2.72168
1994	2.68118
1995	2.57088
1996	2.44699
1997	2.34403
1998	2.2511
1999	2.17562
2000	2.11212
2001	2.03553
2002	1.94866
2003	1.87736
2004	1.82595
2005	1.78117
2006	1.77318
2007	1.74682
2008	1.61434
2009	1.34509
2010	1.00071
2011	0.61914
2012	0.31814
2013	0.20549
2014	0.34917
2015	0.67777
2016	1.06165
2017	1.39317